Well a hallucination would imply you're actually seeing things as if they were in the room with you, not just imagining them in your head / with your eyes closed etc. Is that the case?

You also mentioned you were really tired and on the verge of sleeping... I know I went through a period where I was so sleep deprived that my body/brain would enter into a sleep state before I was unconscious. I would sometimes hallucinate sounds as though somebody was speaking to me in the room, but nobody was there. So, if you're really really tired, your brain might start dreaming before you lose consciousness, and this would come across as a hallucination.